Kumitachi

Kumitachi are two person kata. Each Kumitachi presents the student
with a different attack and potential defense. There are two roles in
each Kumitachi. The Uchidachi is the attacker who initiates the
confrontation. The Shidachi is the defender who must react with a
defensive action followed by a counter-attack. They teach the student
how to gauge distance, predict an opponents movement, and react to different
attacks. You can find details on the kumitachi at
Toyama Ryu
Kumitachi.

A set of Kumitachi begins and ends with a bow to your training partner.
In general all forward steps start with the right foot and all backwards
steps start with the left. Every attack should also have a Kiai. The
Uchidachi (Attacker) leads all movement up to the point they would be struck
down. The Shidachi (Defender) leads all movement after that. The person
leading movement defines positions and form. The person following adjusts to
those positions. For instance – the Shidachi might place their sword into a
Chudan Kamae position at the end of a Kumitachi and the Uchidachi would make
sure the kissaki were level and overlapping the proper amount. Kumitachi end
with five short steps back to their original starting position.